III.6. Interval

There are two modes to specify the time interval of ephemeris. The first one (Near opposition ephemerides mode) is used only for calculation of near-opposition ephemerides. This mode is applicable if the date of opposition belongs to the basic interval of 16 months from November of the year preceding to the title one to February of the subsequent one. In this case the ephemeris is centered at the nearest standard moment (its Julian day minus 0.5 is exactly divisible by 10) which precedes or coincides with the moment of opposition of minor planet in specified year. User should enter the number of the year (it may be the title year or preceding one or subsequent one) and select desirable length of ephemeris interval by scrolling the list of possible values (selection is possible with the limits from 20 to 120 days) and then enter wanted ephemeris step. It may be equal to any positive value. In case of sufficiently great step the ephemeris will contain only one line. It is meaningless to assign very small step, say less than 0.01, as the run may last too much time.

The Arbitrary interval mode is more general. It permits the limits of interval to be specified explicitly. They should be introduced within the boundaries from 1800 to 2100 as year, month, day, and its fraction, e.g. 20020610.8 or as Julian day. Lower limit can be less, equal or greater than upper one. Step must be specified as positive value or zero. In case lover limit is greater than upper one the ephemeris is calculated as if step is negative.

It makes no sense to assign step less than 10**(-5) as fraction of day is displayed with five decimals only.